Draught bar



Jan. 12, 1954 w ALLEN 2,665,902

DRAUGHT BAR Original Filed June 25, 1942 n? It I N VEN TOR.

A TTiOR/VEVS Patented Jan. 12, 1954 DRAUGHT BAR Raymond W. Allen, Akron, Ohio, assignor to The Firestone Tire & Rubber Company,

Akron,

Ohio, a corporation of Ohio Application June 20, 1946, Serial No. 678,106, now Patent No. 2,476,825, dated July 19, 1948, which is a division of application Serial No. 448,472,

June 25, 1942,

now Patent No. 2,415,024, dated January 28, 1947. Divided and this application December 14, 1948, Serial No. 65,101

This application is a division of application No. 678,106, filed June 20, 1946, now Patent No. 2,476,825, dated July 19,1948, which is a division of application No. 448,472, filed June 25, 1942, now Patent No. 2,415,024, dated January 28, 1947.

This invention relates to improvements in draught bars and more particularly for draught bars for gun carriages.

An object of the invention is to provide an improved draught bar adapted to absorb shock.

In the drawing:

Figure 1 is a side elevation of a draught bar embodying the present invention;

Figure 2 is a plan view of the draught bar connector with the lunette mechanism shown in longitudinal section.

Referring to the drawing in detail it will be seen that the inner end of a draught bar 62 is provided with means for pivotal connection to a gun carriage or other vehicles through the medium of a clevis link 63 attached to the carriage or vehicle not shown. The draught bar comprises a tubular shell or connector 99 having one end portion forked to embrace the clevis link 63 and apertured to receive the pivot pin 98. A locking pin I is insertable through the forked portion of the connector and engages in a recess in the clevis link 03. The other end of the draught connector is provided with a lunette IOI for attachment to a limber by a pintle hook. Lunette IOI has an integral shank portion comprising a cylindrical portion I02 and a reduced cylindrical portion I03 extending axially therefrom. As shown in the drawing, there is formed at the reduced cylindrical portion a shoulder I20. Portion I02 is suitably journaled within tubular shell 99. The lunette shank is substantially less in diameter than the inside diameter of the connector walls whereby to provide an annular chamber therebetween in which are disposed a plurality of rubber collars I 04 between washers I 05 abutting the shoulder I20 of shank portion I02 and washers I06 at the terminal end of the shank. A centrally apertured stop member I07 is positioned within the connector adjacent an annular shoulder E08 in the shell, said stop member having a central aperture of sunicient size to allow washer I09, clamped to the end of reduced shaft portion I03 by nut IIO, to pass therethrough, while preventing washers 106 from so doing. The rubber collars I 04 have outer and inner surfaces concave in axial cross section to provide space between the shank and the inner shell wall to enable rubber to flow upon axial compression of collars I04. Members I04 are 2 Claims. (Cl. 267-69) separated by washers IMa. Double acting shock absorption is obtained between the lunette and the connector in the following manner to eliminate vibrations between the draught means ciand the carriage.

Compression forces between the members resulting in axial movement of the lunette toward the shell 99 cause compression of the rubber collars 104 by reason of washers I05, backed against the shoulder I20 of cylindrical portion 102, being forced inwardly of the shell to compress said collars. Forces tending to withdraw the lunette from the shell cause washers I06, backed against retention washers I09, to move axially outward of shell 99 to compress collars 00, washers I05 being restrained against outward movement by a threaded plug III which forms a closure for the outer shell end and provides support for a bushing H2 in which the shank portion I02 is journaled. Since rubber flows readily but will not compress, it is evident that resistance to relative movement between the shell and lunette shank is limited to the amount. of axial movement therebetween required to. cause distortion of the collars I04 suflicient to completely eliminate said concave portions of: the rubber collars and to fill the space between; the shank, shell and the slidable rigid washers.

I05 and I06. The present connector device pro-'- vides substantial initial movement between the lunette and shell, with a sharply progressive increase in resistance to relative movement therebetween as the rubber is forced radially to fill the chamber space.

What is claimed is:

1. A rubber spring of the character described comprising a connector with a tubular bore in the outer end thereof, a lunette having a shaft with a cylindrical shank portion in journalled relation to the outer end of said connector and a reduced cylindrical portion concentrically disposed within the bore in spaced relation to the walls thereof, a series of collars of rubber-like material encircling said cylindrical portion in longitudinal slidable relation with said cylindrical portion and with the walls of said bore, said collars having radially inner and outer marginal portions engaging said cylindrical portion and connector, the radially inner and outer portions of the said collars being concave in cross section to permit rubber flow upon axial compression of the collars, a shoulder on said shaft adjacent said lunette, a rigid washer slidably mounted on said shaft intermediate said collars and said shoulder, said washer abutting said shoulder when said shank moves inwardly of the bore, a stop member disposed at the end of said bore away from said lunette, a rigid washer slidably mounted on said shaft intermediate said stop member and said collars, said last-mentioned washer abutting said stop member when said shank moves inwardly of said bore, whereby relative movement between the concentrically disposed portion of said shank and housin causes said collars to be axially compressed and the rubber to be progressively distorted into the concave portions thereof to be radially expanded into frictional contact with the surface. of said bore and shank.

member and said collars, said last-mentioned 2. A rubber spring of the characterv described 415 comprising an elongated rigid housing with a cylindrical bore therein, a lunette having a shaft mounted in said bore in spaced and axially slidable relation to the sides of said cylindrical 'bore, a series of rubber collars encircling said shaft and hawing radially inner andeouter marginal portions engaging said shaitand the side of said housing respectively said marginal "portions be ing concave in cross :section and the concavity normally being out of engagement withsaidshaft and housing, said shaft "and housing having means associated therewith, :said means comprising a shoulder on said shaft adjacent said lunette, a rigid washer slidably mounted on said washer abutting said stop member when said shaft moves inwardly of said bore, whereby said collars are subjected to axial compressive forces in two directions thereby being distorted radially inwardly and outwardly progressively pressing the entire surface of said marginal portions against the sides of said shaft and bore respectively.

RAYMOND W. ALLEN.

References Cited the file Of this patent UNITED STATES PATENTS Number Name Date 1,819,393 Staley Aug. 18, 1931 1,871,390 Reynolds Aug. 9, 1932 1,991,684 Ketel Feb. 19, 1935 FOREIGN PATENTS Number Country Date "385,912 France Apr. 2, 1908 762,631 France Jan. 22, 1934 III In" 

